>>714737268The fact that the only aspect of SHMUP you can point out as positives are shallow set dressing stuff is telling.
The core gameplay is just wiggling back and forth to avoid projectiles while hitting the attack button as fast as you can. The core defining gameplay that makes a SHMUP is boring.
It doesn't matter what you swap out the sprites with, be it a jet, or a magical girl, or a fairy, or whatever, that doesn't change the dull gameplay.